The primary difference between HTTP and HTTPS is that HTTPS includes an additional layer of security through SSL/TLS encryption. While HTTP (Hypertext Transfer Protocol) is used for transmitting data over the web without encryption, HTTPS (Hypertext Transfer Protocol Secure) ensures that communications between the web server and browser are encrypted, protecting against eavesdropping, tampering, and man-in-the-middle attacks. This secure communication is crucial for online transactions, handling sensitive information, and improving overall user trust. The implementation of HTTPS has become a standard practice for secure web browsing today.